Synthetic organosilane compounds useful as lubricants in glass sizing compositions

ABSTRACT

An aqueous glass fiber sizing composition acetate file former and an effective amount of a lubricant additive having the formula: ##STR1## where R is an alkyl or alkenyl group of 6 to 20 carbons, A is a divalent organic--S--or--NH--group, R 1  is an alkyl group of 1 to 4 carbons, m is or 1 and n is 0 to 10 with the proviso that when n is O, m is also O.

This application is a division of application Ser. No. 07/581,811, filedSep. 13, 1990 and now U.S. Pat. No. 5,120,480.

BACKGROUND OF THE INVENTION

The present invention relates to a sizing composition used in glassfiber reinforced resin and plastic articles and to selected syntheticorganosilane lubricants incorporated therein.

It is well known to use glass fibers to reinforce polymeric materials.These glass fibers are provided in various forms such as mats includingchopped strand mats and continuous strand mats; rovings which arebundles of glass fiber strands wound up in parallel, i.e. without twist;woven rovings; and chopped and milled fibers. They are produced by aprocess called forming wherein fibers are drawn at a high rate of speedfrom molten glass through tiny orifices or tips in a heated platinumbushing (a fiber-drawing furnace) then attenuated into a multi-filamentstrand. The glass fibers so produced must be protected frominterfilament abrasion during formation and processing and must be madecompatible with the polymeric materials they are to reinforce. This isusually accomplished by treating the glass fibers with a sizingcomposition.

Basically, a fiber size must provide the following characteristics tothe strand of filaments: a) good adhesion between glass fiber andpolymer; b) good cohesion between filaments within a strand; c) certainhandling characteristics like hardness, softness, choppability, etc.imparted by careful selection in terms of type and quantity ofcomponents; d) protection of the strand during its various processingstages and e) other desired characteristics such as antistatic andelectrical properties.

Sizing compositions are well known in the art and include the starchbased sizes used in the formation of glass fiber weavers yarns and fibersizes designed for the reinforcement of thermosetting resins andthermoplastics. The latter type sizes, sometimes referred to as plasticssize, typically comprising a film-forming polymeric or resinouscomponent, a coupling or keying agent and a lubricant. The majority offiber sizes for general purpose reinforcing materials use polyvinylacetate as a film-former, Polyesters, epoxides, polymethyl methacrylateand polystyrene are also used as film-formers, sometimes alone andsometimes as copolymers or blends with polyvinyl acetate. Coupling orkeying agents (also called adhesion promotors) improve the bond betweenthe polymeric resin and glass and typically are organo-metallic, in mostcases organo-silicon compounds. Common lubricants used are cationicsurface-active agents such as a fatty acid amine or a fatty acidquaternary ammonium compound.

Many different sizing compositions, having formulations which areadapted to provide the various properties desired in the glass fiberproducts, have been developed. Typical compositions are disclosed in"The Manufacturing Technology of Continuous Glass Fibers" by K. L.Lowenstein, second edition, Elsevier Science Publishing Company, 1983wherein a number of film formers, coupling or keying agents, lubricantsand other components such as plasticisers, emulsifiers, antistaticagents and miscellaneous other materials are disclosed. More specificglass fiber sizing compositions are disclosed in the following patents.In U.S. Pat. No. 3,865,768 issued Feb. 11, 1975, a glass sizingcomposition to provide lubricity in the formation of rovings and whichis a compatible with polyester resins is disclosed and comprises a poly(vinyl acetate) latex film former, a polyester compatible silane, atleast one alkyl amide reaction product of an alkyl carboxylic acid andan ethylene amine and a nonionic surfactant derived from halogentatedfatty acid containing oil. U.S. Pat. No. 3,933,711 issued Jan. 20, 1976discloses an aqueous sizing composition comprising polyvinyl acetate, afatty acid amide lubricant, methacrylate chronic chloride and gamma(ethylene diamine) propyl trimethoxy silane. U.S. Pat. No. 4,284,538issued Aug. 18, 1981 discloses an aqueous dispersion sizing compositioncontaining a cationic imidazoline; an aliphatic aromatic and/orpolymeric ester and polyethylene.

Other sizing compositions are disclosed in U.S. Pat. No. 4,341,877issued Jul. 27, 1982 which shows a composition comprising an epoxidizedpolar thermoplastic copolymer, an organosilane coupling agent and anonionic, cationic or anionic lubricant and in U.S. Pat. No. 4,448,910issued May 15, 1984 wherein the composition includes an emulsified epoxyresin and 3-chloropropyltrimethoxy silane as the coupling agent. U.S.Pat. No. 4,489,131 issued Dec. 18, 1984 discloses a size for glassfibers employed in reinforcing polypropylene comprising an oxidizedpolyolefin, a carboxylated high molecular weight elastomer as a filmformer, an amino silane and a selected organic acid.

In producing glass reinforced fibers, as disclosed above, many differentsizing compositions have been used. While lubricants to aid in theprocessibility of the glass fibers are generally used, in many instancesthey can have a detrimental effect on same properties. For example, theyreduce the strength and stiffness of a glass reinforced product.

Accordingly, there is the need for a sizing composition, for use inproducing glass fiber reinforced articles, which contains a lubricantand which has improved strength and stiffness properties.

SUMMARY OF THE INVENTION

This invention relates to an aqueous sizing composition for glass fiberreinforced polymeric materials comprising a polyvinyl acetate filmformer and an effective amount of a lubricant additive having theformula: ##STR2## where R is an alkyl or alkenyl group, straight orbranched chain, having 6 to 20 carbon atoms, A is a divalent organic,--S--or --NH--group, R¹ is an alkyl group of 1 to 4 carbon atoms, m is 0or 1 and n is 0 to 10 with the proviso that when n is 0, m is also 0.

Another embodiment of this invention involves the novel organo silanecompounds (I) used in the aforementioned sizing composition where m is1.

DETAILED DESCRIPTION OF THE INVENTION

The organosilane compounds (I) used in the glass fiber sizingcompositions of this invention can be prepared by reacting selectedsilane compounds with organo compounds having a long chain hydrocarbongroup R, both compounds containing reactive sites. More particularly,the organosilane compounds (I) can be prepared in three or more ways.The first type of reaction is between an amine or sulfhydryl containingtrialkoxysilane and a long chain alkyl or alkenyl containing compoundhaving a reactive site such as an epoxide, an isocyanate, a halide, anester or an anhydride. The second type of reaction is one between anepoxy containing trialkoxy silane and a long chain alkyl or alkenylcontaining compound having a reactive site such as an amine, acarboxylic acid or a sulfhydryl. The third type of reaction is onebetween a methacryloxyalkyl containing trialkoxysilane and a long chainalkyl or alkenyl containing compound having a reactive site such as anamine or a sulfhydryl.

In the above formula I representing the organosilane compounds, R is analkyl or alkenyl group having 6 to 20 carbon esters, preferably 8 to 20carbons, A is a divalent organic, --S--or --NH--group, R¹ is an alkylgroup of 1 to 4 carbon atoms, preferably 1 to 2 carbons, m is 0 or 1,preferably 1 and n is 0 to 10, more particularly 1 to 10 and preferablyto 1 to 5 with the proviso that when n is 0, m is also 0.

As noted above, A is a divalent organic, S--or --NH--group and is theresidual component resulting from the reaction of selected silanecompounds with organo compounds that contain reactive sites. Whenfollowing such reactions the divalent A group will have a typicalstructure such as: ##STR3##

It is further noted that the organosilane compounds (I) used in theglass fiber sizing compositions may comprise a mixture of such compoundsand this may result from the method of preparation as illustrated below.

The preparation of the organosilane compounds (I) by reacting a signalcompound with a long chain organo compound can be illustrated by thefollowing reaction wherein octenyl succinic anhydride is reacted withaminopropyltriethoxy silane. ##STR4##

The long chain organo compounds which may be used in preparing theorganosilane compounds (I) have the following general formula:

    R.sup.2 X

where R² is an alkyl or alkenyl group having 6 to 20 carbon atoms,preferably 8 to 20 carbons and may be a straight or branch chain. X is agroup having a reactive site such as an amine (--NH₂), a carboxyl(--COOH), a sulfhydryl or mercapto (--SH), an epoxy ##STR5## anisocyanate (--N=C=O), a halide, an ester (--COOR₄) and an anhydride.

The organosilanes used in preparing the organosilane compounds (I) havefollowing general formula: ##STR6## where R¹ is an alkyl of 1 to 4carbon atoms, preferably 1 to 2 carbons, n is 0 to 10, preferably 1 to 5and Y is a group having a reactive site such as an amine (--NH₂), asulfhydryl or mercapto (--SH), an epoxy ##STR7## or a methacryloxy##STR8##

One group of especially useful long chain organo compounds are theanhydrides, particularly the alkenyl succinic anhydrides (ASA) havingthe following general formula: ##STR9## where R is an alkyl or alkenylgroup having 6 to 20 carbon atoms, preferably 8 to 20 carbons. The Rgroup may be straight or branched chain and therefore would includesubstituents of structures such as: ##STR10## where R⁵ and R⁶ may be thesame or different alkyl groups. Anhydride compounds of this type arefurther described in U.S. Pat. No. 2,661,349 issued Dec. 1, 1953 toCaldwell et al.

One group of especially useful organosilanes as described above are theamine containing compounds which for example may be reacted with a longchain organo anhydride compound resulting in an organosilane of thestructure where A in formula I is: ##STR11##

It is further noted that organosilane compounds (I) of the type where mis 0 are known in the art as disclosed for example in U.S. Pat. Nos.3,488,318 issued Jan. 6, 1970 and 4,863,992 issued Sep. 5, 1989.

Polyvinyl acetate is the film-former used in the sizing composition ofthis invention. It may be used alone or may include copolymers such aspolyesters, epoxides, polymethyl methacrylate and polystyrene.

A keying or coupling agent (also referred to as an adhesion promoter) isgenerally included in the sizing composition. While in some instances,sizing compositions containing the organosilane agents (I) do not need akeying agent, usually a compound of this type is included.Keying/coupling agents typically used are organo-metallic and in mostcases organo-silicon compounds. Illustrative keying/coupling agents thatmay be used are methacrylate chromic chloride and other metal complexesand organosilanes such as vinyltriethoxy silane,gamma-meathacryloxypropyltriethoxy silane and 3-aminopropyltriethoxysilane.

It is desired to adjust the pH of the sizing composition generally onthe acid side to maintain a stable fiber size with good performance.This is usually in the pH range of about 2 to 7 and more preferablyabout 5 to 6.5 and can be accomplished by adding acetic acid.

Other conventional glass forming size additives such as plasticizers,surfactants, emulsifiers, antistatic agents, wetting agents, etc., maybe included in the sizing composition of this invention if desired.

The amounts of components used in the sizing composition will varywithin the typical ranges and depending on the desired properties of thesized fibers. Generally, the aqueous sizing composition of thisinvention will comprise from about 0.2 to 20% by weight of film-former,preferably about 0.5 to 5%; from about 0.05 to 3% of lubricatingadditive I, preferably about 0.1 to 1% by weight; from about 0 to 3% byweight of keying/coupling agent preferably from about 0.1 to 1% and thebalance being water. All of the above weight percents are based on thetotal weight of the sizing composition.

The sizing composition of this invention can be prepared usingconventional techniques and means known in the art. The dilute aqueoussizing composition can be applied to glass fibers to form a size coatingthereon by any convenient method, such as drawing the fibers to be sizedacross a rotating or stationary roll wet with sizing composition andthen drying the composition so applied after collecting the fiber bywinding onto a rotating collet or forming tube. Usually the sizingcomposition will be applied to glass fibers during continuousmanufacture. This typically involves the drawing of molten glass into aplurality of filaments from a temperature controlled bushing located onthe underside of a furnace. The whole emerging fan of individual fibers,called filaments, passes through a light water spray and then over anapplicator which transfers a protecting and lubricating size onto thefilaments before they are grouped together on a suitable means, such asa shaped shoe, into a bundle of filaments called a strand. The strand offibers is then wound on a rotating cylinder, called a collet, and driedbefore further processing where they are converted into desiredarticles.

The following examples are further illustrative of the invention and arenot intended to be construed as limitations thereof. All parts andpercentages are given by weight and all temperatures in degrees Celsiusunless otherwise noted.

EXAMPLE I

An amino organosilane compound of structure I was prepared by reactingoctenyl succinic anhydride with aminopropyltriethoxy silane at roomtemperature for 2 hours. A clear liquid product having the followingstructure and identified as Product A, was obtained: ##STR12##

Another compound of structure I was prepared in a similar manner byreacting tetradecenyl succinic anhydride with aminopropyltriethoxysilane at 60° C. for 1.5 hours. This product, called Product B had thefollowing structure: ##STR13##

EXAMPLE II

Glass fiber sizing compositions were prepared using the productsobtained in Example I (Products A and B), a file-former, Resyn 1971 anepoxidized polyvinylacetate copolymer (3% epoxy functionality) availablefrom National Starch and Chemical Co., an adhesion promotor, A-174 whichis gamma-methacryloxypropyltriethoxysilane available from Union CarbideCorp. and having the following formulation:

    ______________________________________                                        Resyn 1971      9.50%                                                         Product A or B  0.3%                                                          A-174           0.7%                                                          Acetic Acid     0.05%                                                         Water           89.45%                                                        ______________________________________                                    

Glass fibers were sized with the above described sizing compositions.The glass was air dried and cured at 130° C. and layered into a curingpolyester resin and left overnight. Laminates comprising twelve layersof glass (about 0.1 inches) were made and heat cured at 150° C. Thelaminates were then sawed into 1"×5" test bars and broken on an Instronapparatus using a three point loading test to determine the breakingstrength. Samples were also boiled for 24 hours before testing to checktheir moisture and temperature resistance. The results are shown in thefollowing table where a comparative sample using a resin formulationwherein Emery 6760, a standard lubricant comprising an amine salt offatty acid, was substituted for the lubricant Product A or B. Additionalsamples without the silane adhesive promotor (A-174) were also tested.

                  TABLE I                                                         ______________________________________                                        Breaking Strength                                                             (pounds)                                                                      Conditions                                                                             Product A Standard  Product B                                                                             Standard                                 ______________________________________                                        Test Sample w/adhesion promotor                                               Dry      97.5      83.0      92.0    86.4                                     24 hr. boil                                                                            59.3      44.2      57.0    45.0                                     Test Sample w/o Adhesion Promotor                                             Dry      62.6      60.6      63.1    60.1                                     24 hr. boil                                                                            24.3      23.0      25.8    22.0                                     ______________________________________                                    

The results show that the sample sizing compositions of this inventionusing Product A or B clearly have a higher breaking strength than thecomparative sample using the standard lubricant both with and withoutuse of the adhesion promotor. The compositions of this invention alsoexhibited greater stiffness than the standard comparative sample.

EXAMPLE III

An organosilane compound of structure I was prepared by reactingisostearic acid with gamma-glycidoxypropyltriethoxysilane. The product(C) having the following structure was obtained. ##STR14## where R isC₁₇ H₃₅.

EXAMPLE IV

An organosilane compound of structure I was prepared by reacting oleylamine with gamma-glycidoxypropyltrimethoxysilane to give product Dhaving the following structure: ##STR15## where R is C₁₈ H₃₅.

EXAMPLE V

An organosilane compound of structure I was was prepared by reactingdodecanethiol with gamma-glycidoxypropyltrimethoxysilane. The product(E) having the following structure was obtained. ##STR16## when R is C₁₂H₂₅.

EXAMPLE VI

Glass fiber sizing compositions similar to those in Example II wereprepared using the products of Examples III and IV, ie. C and D inamounts of 0.3% by weight without an adhesion promotor. The breakingstrength of the unboiled samples was determined as in Example II usingan Instron apparatus.

The breaking strength of the sample containing Product C was 90.2 lbscompared to 85.1 lbs for a resin formulation wherein Emery 6760, astandard lubricant comprising an amine salt of fatty acid, wassubstituted for the lubricant Product C (both results represent anaverage of five measurements).

The breaking strength of the sample containing Product D was 95.5 lbscompared to 82.6 for the comparative sample (both results representingan average of five measurements).

The results show the higher breaking strength for sizing compositions ofthis invention containing Products C and D as compared to the testsamples containing standard lubricants.

What is claimed is:
 1. An organosilane compound having the structure:

    R--A--(CH.sub.2).sub.n --Si--(OR.sup.1).sub.3

where R is an alkyl or alkenyl group, straight or branched chain, having6 to 20 carbon atoms, R¹ is an alkyl group of 1 to 4 carbon atoms, A isa --S--, --NH--or divalent organic group which contains an O, S or Ngroup and n is 1-10.
 2. The compound of claim 1 wherein the A group hasthe structure selected from the group consisting of: ##STR17##
 3. Thecompound of claim 2 wherein R has 8 to 20 carbon atoms.
 4. The compoundof claim 3 wherein R¹ has 1 to 2 carbon atoms and n is 1 to
 5. 5. Thecompound of claim 1 wherein R has 8 to 20 carbon atoms.
 6. The compoundof claim 5 wherein A is a divalent organic group selected from the groupconsisting of: ##STR18## and mixtures thereof.
 7. The compound of claim6 where R has the following structure: ##STR19## where y is 4 or 10 andn is
 3. 8. The compound of claim 5 wherein R¹ has 1 to 2 carbon atomsand n is 1 to
 5. 9. The compound of claim 8 wherein A is a divalentorganic group having the structure: ##STR20## and mixtures thereof, andR has the following structure: ##STR21## where y is 4 or 10 and n is 3.